Black oil conversion catalyst

ABSTRACT

ASPHALTENE-CONTAINING HYDROCARBONECEOUS CHARGE STOCKS ARE REACTED WITH HYDROGEN IN CONTACT WITH A CATALYTIC COMPOSITE OF AT LEAST ONE METAL COMPONENT SELECTED FROM THE GROUP CONSISTING OF THE BORIDES AND BOROHYDRIDES OF THE METALS FROM GROUPS IV, V AND VI. A SLURRYTYPE PROCESS, WHICH MAY BE EFFECTED EITHER WITH THE METALLIC COMPONENT BEING COMPOSED WITH A POROUS CARRIER MATERIAL, OR WITH THE UNSUPPORTED METALLIC COMPONENT, AND ADMIXED WITH THE FRESH FEED CHARGE STOCK.

United States Patent 3,796,671 BLACK 01L CONVERSION CATALYST William K.T. Gleim, Island Lake, 111., assignor to Universal Oil Products Company,Des Plaines, Ill. No Drawing. Filed Aug. 23, 1972, Ser. No. 282,998 Int.Cl. B01j 11/82 U.S. Cl. 252-432 8 Claims ABSTRACT OF THE DISCLOSUREAsphaltene containing hydrocarbonaceous charge stocks are reacted withhydrogen in contact with a catalytic composite of at least one metalcomponent selected from the group consisting of the borides andborohydrides of the metals from Groups IV, V and VI. A slurrytypeprocess, which may be effected either with the metallic component beingcomposited with a porous carrier material, or with the unsupportedmetallic component, and admixed with the fresh feed charge stock.

APPLICABILITY OF INVENTION The invention herein described is adaptableto a process for the conversion of heavy, asphaltene-containing petroeumcrude oils into lower-boiling hydrocarbon products. More specifically,the present invention is directed towards a catalytic process forcontinuously converting atmospheric tower bottoms products, vacuum towerbottoms products (vacuum residuum), crude oil residuum, topped crudeoils, coal oil, oils extracted from tar sands, etc, all of which arecommonly referred to in the art as black oils, and which contain anappreciable quantity of asphaltenic material. In particular, the processaffords a high degree of asphaltene conversion into hydrocarbonsolubleproducts, while simultaneously effecting a substantial conversion ofsulfurous and nitrogenous compounds to reduce sulfur and nitrogenconcentrations.

Petroleum crude oils, particularly the heavy oils extracted from tarsands and vacuum residuum, contain high molecular weight sulfurouscompounds in exceedingly large quantities, being in excess of 1.0% byweight, and often exceeding 3.0% by weight. In addition, these blackoils contain excessive quantities of nitrogenous compounds, highmolecular weight organometallic complexes principally comprising nickeland vanadium, and asphaltenic material. These high molecular weightasphalts are generally found to be complexed, or linked with sulfur andto a certain extent with the organometallic contaminants. An abundantsupply of such hydrocarbonaceous material currently exists, most ofwhich has a gravity less than about 20.0" API. This material isgenerally further characterized in that 10.0% by volume, and generallymore, has a normal boiling point above a temperature of about 1050 F.

The process of the present invention is particularly directed toward thecatalytic conversion of hydrocarbonaceous black oils into distillablehydrocarbon products. Specific examples of black oils, illustrative ofthose to which the present invention is applicable, are a vacuum towerbottoms product, having a gravity of 7.1 API, and containing 4.05% byweight of sulfur and 23.7% by weight of asphaltenes; and, a vacuumresiduum having a gravity of 8.8 API, and containing about 6.0% byweight of asphaltic material. The present invention affords theconversion of the greater proportion of such material, heretofore havingbeen thought to be virtually precluded. The principal difiiculty residesin the lack of a technique which affords many catalytic composites thenecessary degree of sulfur stability, while simultaneously 3,796,671Patented Mar. 12, 1974 producing lower-boiling products from thehydrocarboninsoluble asphaltic material. Asphaltic material consistsprimarily of high molecular weight, non-distillable coke precursors,insoluble in light hydrocarbons and Which, at the conditions required toobtain acceptable desulfurization, agglomerate and polymerize to theextent that the catalytically active surfaces and sites of the catalystare shielded from the material being processed.

Heretofore, in the area of catalytic processing of asphaltene-containingmaterial, two principal approaches have been advanced: liquid-phasehydrogenation and vapor-phase, or mixed-phase hydrocracking. In theformer type of process, liquid-phase oil is passed upwardly, inadmixture with hydrogen, into a fixed-fluidized bed of catalystparticles. Although perhaps effective in converting at least a portionof the oil-soluble organometallic complexes, this type process isrelatively ineffective with respect to the high-boiling asphaltics. Theretention of unconverted asphaltics suspended in a free liquid-phase oilfor an extended period of time, results in polymerization andagglomeration. Some processes have been described which rely primarilyupon cracking in the presence of hydrogen over a fixed-bed of a solidparticulate catalyst. The latter rapidly succumbs to deactivation as aresult of the deposition of coke and metallic contaminants thereon.Furthermore, such a process requires an attendant high capacityregeneration system in order to implement the process on a continuousbasis. Briefly, the,

present invention involves a slurry-type process utilizing a catalyticcomposite of at least one metal component selected from the groupconsisting of the borides and borohydrides of the metals from Groups IV,V and VI of the Periodic Table. The asphaltic material and catalyst aremaintained in a dispersed state within a principally liquid phase whichis rich in hydrogen. Intimate contact is thus aiforded between theasphaltic material and the catalyst, thereby effecting reaction withhydrogen; the liquid phase is itself dispersed in a hydrogenrich gasphase so that the dissolved hydrogen is continuously replenished.

In addition to the hydrocarbon-insoluble asphaltenes, sulfurous andnitrogenous compounds, black oils contain greater quantities of metalliccontaminants than are generally found in lighter hydrocarbon fractions.A reduction in the concentration of the organometallic contaminants,such as the metal porphyrins, is not easily achieved, and to the extentthat the same no longer exert detrimental effects with respect tosubsequent fixed-bed catalytic processing. When a metal-contaminatedhydrocarbon charge stock is subjected to a hydrocracking process, forexample, to produce lower-boiling hydrocarbons, the metals becomedeposited upon the catalyst, steadily increasing in quantity until suchtime as the composition of the catalytic composite is changed to theextent that undesirable results are obtained.

The principal object of the present invention is to provide a moreefiicient process for the hydrorefining conversion of heavyhydrocarbonaceous material containing insoluble asphaltenes. The termhydrorefining, as employed herein, connotes the catalytic treatment, inan cludes the efficient utilization of fixed-bed system. The presentinvention involves the use of a colloidally dispersed catalytic agent ina slurry-type process. The present process affords greater yields of anormally liquid hydrocarbon product which is more suitable forsubsequent processing without experiencing the difficulties otherwiseresulting from the presence of the foregoing contaminating influences.

OBJECTS AND EMBODIMENTS One subject of the present invention is toprovide a more eflicient process for the conversion ofasphaltenecontaining hydrocarbonaceous charge stocks. A corollaryobjective is to provide a novel conversion catalyst.

Therefore, in one embodiment, the present invention is directed toward aprocess for the conversion of a sulfurous, asphaltene-containinghydrocarbonaceous charge stock, which process comprises reacting saidcharge stock with hydrogen and in contact with a catalytic composite ofat least one metallic component selected from the group consisting ofthe borides and borohydrides of the metals from Groups IV, V and VI, andrecovering desulfurized, lower-boiling hydrocarbon products. In anotherembodiment, the charge stock is reacted with hydrogen in the presence ofabout 2.0% to about 30.0% (on a mole basis) of hydrogen sulfide.

In a preferred embodiment, the selected metal boride, or metalborohydride, is unsupported, and is admixed with said charge stock in anamount from about 1.0% to about 30.0% by weight.

SUMMARY OF THE INVENTION From the foregoing embodiments, it is readilyascertained that the process of the present invention involves thepreparation of a colloidally dispersed catalytically active metalliccomponent within the hydrocarbon charge stock from which thecontaminating influences are intended to be removed. The colloidallydispersed catalytic component is a metallic compound selected from thegroup consisting of the borides and borohydrides of the metals fromGroups IV, V and VI. Thus, in accordance with the Periodic Table of theElements, E. H. Sargent and Co., 1964, suitable catalytic metalliccomponents are the borides and borohydrides of titanium, zirconium,hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and/ ortungsten. These compounds are solids, and may be employed in admixturewith the charge stock in and of themselves, or in combination with asuitable refractory inorganic oxide. While any of the Well knownrefractory inorganic oxides may be utilized in combination with themetallic boride, or borohydride, the use of alumina is preferred. Aparticularly preferred prous carrier material is a composite of aluminaand from about 10.0% to about 90.0% by weight of silica. When utilizinga porous carrier material, the catalytic composite is convenientlyprepared by commingling the metallic boride, or borohydride, andfinely-divided carrier material under reducing conditions and subjectingthe resulting mixture to a pilling, or co-extrusion technique under areducing gas atmosphere. The catalytic agent, whether supported, orunsupported, is employed in an amount in the range of about 1.0% toabout 30.0%, based upon the weight of the black oil charge stock.

Briefly, the process is effected by initially admixing the desiredquantity of the catalytic agent with the charge stock. The resultingcolloidal suspension is then passed into a suitable reaction chambermaintained at a temperature within the range of about 225 C. to about500 C. and a pressure of about 500 to about 5,000 p.s.i.g.; the hydrogenconcentration is based upon the quantity of charge stock, and is fromabout 1,000 to about 30,000 s.c.f./bbl. It appears that the presence ofhydrogen sulfide in the hydrogen atmosphere enhances catalytic activityand produces more favorable results; therefore, hydrogen about 2.0% toabout 30.0%. The process may be effected as a batch-type operation, orin a continuous manner in either upward flow, or downward flow. Apreferred technique utilizes an elongated reaction chamber through whichthe reactants are passed in upward flow. The normally liquidhydrocarbons are separated from the total reaction zone product effluentby any suitable means, the remaining metal-containing sludge beingtreated as hereinafter set forth.

The metal-containing sludge is a viscous fluid consisting of thecatalytically active metallic component, unconverted asphaltic material,soluble hydrocarbons, porphyrinic material containing nickel, vanadiumand other metallic contaminants, coke and heavy carbonaceous material,etc. Following the separation of the normally liquid hydrocarbons fromthe metal-containing sludge, the latter is treated with a suitableorganic solvent for the purpose of dissolving residualhydrocarbon-soluble material resulting from the conversion of theinsoluble asphaltenic compounds. Any well-known organic solvent may beemployed for the dissolution of the organic-soluble material in thesludge, and the resulting solution may be subjected to further reactionwith hydrogen by recycling the same to combine with fresh hydrocarboncharge stock. The remaining portion of the sludge, containing thecatalytically active agent, is combined with fresh hydrocarbon chargestock and again reacted with hydrogen as aforesaid. In order to preventa build-up of coke, unconverted asphaltenic material and othercarbonaceous residue, a controlled portion of the sludge will bewithdrawn from the process and sent to a suitable metals recoverysystem.

The following examples are presented to illustrate the process of thepresent invention and the effectiveness thereof in convertingasphaltenic material. It is not intended that the present invention beunduly limited to the method, charge stock, catalytic agent and/oroperating conditions employed in these illustrations.

EXAMPLES The hydrocarbon charge stock is a vacuum tower bottoms having agravity of 8.8 API, containing 6.0% by weight of asphaltenic material,3.0% by weight of sulfur,

and 4,300 p.p.m. by weight of nitrogen; the 20.0% volusulfide will bepresent in an amount within the range of metric distillation temperatureis about 1055 F.

Example I In this example, the criteria employed to indicate the degreeof conversion, particularly with respect to asphaltenic material, is thecolor index of the product. Obviously, the lighter the color of theproduct, the lower the color ndex and the greater the degree ofconversion. The color index is determined by UOP Method 707-71, basedupon the information found in Analytical Chemistry, volume 34, pages694-700, 1962.

The charge stock is employed in an amount of about 200 grams, and isadmixed with about 20.0 grams (10.0% by weight) of titanium borohydride.The charge stock and catalytic agent are intimately commingled in an1,800 cc. rotating autoclave with hydrogen at a pressure of atmospheres.Upon heating to a temperature of 400 C., the pressure increases to about200 atmospheres. These condrtions are maintained for a two-hour period,after which the autoclave is cooled and depressured, and the contentsseparated to provide a metal-containing sludge and the normally liquidproduct efliuent. The latter is analyzed for color index and gravity,and a significant improvement is observed; the gravity is increased from8.8 API to about 25.4 API and the color index is decreased from about150.0 to about 2.0.

Example II In this example, the hydrocarbonaceous black oil is a heavyvacuum tower bottoms product having a gravity of 7.0 API andcontaminated by the presence of 6,060

p.p.m. of nitrogen, 4.0% by weight of sulfur, more than 450 p.p.m. oforganometallic contaminants, and about 24.0% by weight ofpentane-insoluble asphaltenic material. The charge stock, in an amountof about 200 grams, is admixed with 25.0 grams of unsupported vanadiumborohydride, the mixture being placed in the rotating autoclave andpressured to about 100 atmospheres with hydrogen. The contents of theautoclave are heated to a temperature of about 425 C., the pressureincreasing to about 215 atmospheres. These conditions are maintained foran eight-hour period, after which the autoclave is depressured, cooledand the contents separated to provide a normally liquid hydrocarbonproduct. The latter indicates a gravity of about 338 API, 0.2% by weightof insoluble asphaltics, 450 p.p.m. of nitrogen and 0.88% by weight ofsulfur.

The foregoing specification and examples clearly illustrate the methodby which the present invention is effected and the benefits to beafforded through the utilization thereof. The normally liquidhydrocarbon product is substantially free from asphaltic material, andhas been signi-ficantly decontaminated with respect to theconcentrationof sulfurous and nitrogenous compounds.

I claim as my invention:

1. A catalytic composite of at least one metal component selected fromthe group consisting of the borides and borohydrides of the metals fromGroups IV-B, V-B and VI-B combined with a porous carrier material.

2. The catalytic composite of claim 1 further characterized in that saidporous carrier material is a refractory inorganic oxide.

3. The catalytic composite of claim 1 further characterized in that saidporous carrier material is alumina.

4. The catalytic composite of claim 1 further characterized in that saidporous carrier material is a composite 6 of alumina and from about 10.0%to about 90.0% by weight of silica.

5. The catalytic composite of claim 1 further characterized in that saidmetal component is a Group IV-B metal boride, or metal borohydride.

6. The catalytic composite of claim 5 further characterized in that saidmetal component is titanium boride, or titanium borohydride.

7. The catalytic composite of claim 1 further characterized in that saidmetal component is a Group V-B metal boride, or metal borohydride.

8. The catalytic composite of claim 7 further characterized in that saidmetal component is vanadium boride, or vanadium borohydride.

References Cited UNITED STATES PATENTS 2,728,758 12/1955 (Field et a1252432 X 3,640,817 2/1972 OHara 252-432 X OTHER REFERENCES Borides,Silicides and Phosphides, Aronsson et a1. Published by John Wiley & SonsInc., New York, NY. (1965) pp. 13 and 14.

Heal; Recent Studies in Boron Chemistry, The Royal Inst. of Chem,Lectures, Monographs and Reports, 1960, No. 1, pp. 18-21.

PATRICK P. GARVIN, Primary Examiner US. Cl. X.R.

